PROJECT SUMMARY ? CORE 1 Glioblastoma (GBM) remains amongst the most deadly and difficult to treat forms of brain tumors. We have been interested in using oncolytic viruses, based on herpes simplex virus type 1 (HSV-1), as a selective tumor- killing virus. Considerable effort in the vector development resulted in the engineering of oncolytic HSV vectors (oHSV) such as rQNestin34.5 and KGN-4:T124 that are non-toxic for normal cells, yet capable of selective replication in GBM tumor cells. Both of these oHSV will enter into Phase-I clinical trials within 2017. The overall hypothesis of the Program Project is to test newly engineered armed versions of these oHSV in immune competent mouse models. In order to effectively use oHSV in animal tumor models it is necessary to propagate and purify oHSV to high titers. Efforts in process development have resulted in scalable systems capable of manufacturing rQNestin34.5, KGN-4:T124 and other oHSVs. My laboratory has spent considerable time developing refined and novel methodologies to improve virus production, purification and quality assessment to provide high quality vector stocks with dramatically reduced levels of protein and DNA contaminants (>99% removal) that can contribute to toxicity, immunity and biodistribution as well as confound in vivo efficacy studies. Our efforts in process development have resulted in scalable systems capable of manufacturing these vectors for pre-clinical efficacy and safety testing resulting in a 10 to 30-fold increase in overall virus yield and a corresponding 60-fold increase in concentration of the virus. The Core is in the unique position of being one of a few sites for oHSV virus vector production, purification and quality assessment testing. This extensive expertise along with our prior collaborative interaction consisting of 33 oHSV vector stocks produced and distributed to the 4 Projects since 2012, supports the overall success of the role of the Pre-Clinical Vector Core in the current proposal. The primary goal of the Core 1, that received a superior rating when the P01 was reviewed last, is to provide large quantities of GLP-grade concentrated and purified oHSV vectors: (i) rQNestin34.5 and armed derivatives; and (ii). KGN-4:T124 and armed derivatives to each of the 4 projects. The oHSV Pre-Clinical Vector Core will work with the projects to provide optimal vector quantity and purity while providing the support necessary to successfully exploit the available technology. We will continue to refine our production, purification and assessment systems. Should any of the engineered oHSV vectors tested in the projects prove efficacious, the Core would provide support to cGMP facilities for transfer of the production/purification technology of large-scale oHSV manufacture for possible Phase-I human clinical trials.